The invention relates to the protection of devices, and, more particularly to the protection of vehicles against unauthorized use, including theft.
There are many protective systems, including anti-autotheft systems, on the market today. Most put heavy emphasis on alarms which are triggered when a thief enters a vehicle, or when motion or breakage is detected.
Some of the existing anti-autotheft systems incorporate an "inhibit start" mechanism. The simplest inhibit start makes use of key which is inserted into a key slot and operated. This arrangement, however, poses only a temporary deterrent. Present key systems can be compromised by dismantling and making correct connections to the control wires.
When the key lock is in a steering column, the thief simply dismantles the steering column and reconnects the wires connected to the key switch to eliminate the need for a key.
Other restraining systems are equally ineffective.
Where a steering wheel is looked to an accessory of the vehicle, the thief simply bypasses the restraint and places the vehicle in operation.
Warning systems are also ineffective. A clever thief either disables or ignores them. The accidental tripping of sound emitting warning devices is so well known that the alarm is typically ignored.
Electronic units that emit tracing signals, on the other hand, are of assistance in recovering vehicles once they are stolen, but they do not hinder the initial theft. Moreover, such units are cumbersome and expensive.
Complexity, expense and ineffectiveness also characterize prior art of the kind for attempting to protect an automobile against theft disclosed in Hauer U.S. Pat. No. 5,006,843; Nieuwkoop, U.S. Pat. No. 4,864,292; Fukamachi et al, U.S. Pat. No. 4,862,139; Adkins et al U.S. Pat. No. 4,463,340; and Adkins U.S. Pat. No. 4,438,426.
Thus Hauer discloses a complex security system in which a micro-chip code module is mounted inside a motor accessory. The micro-chip code module is a silicon substrate with an added semiconductor switch in the engine compartment of the vehicle, and is controlled from a microprocessor in the dashboard of the vehicle.
The microprocessor includes a keyboard and a code sender with components joined by a data bus. The code sender components include a processor, a program memory, a data memory, a line interface and a key board interface.
The keyboard interface, in turn, connects a data bus to a keyboard. The line interface connects the data bus of the code sender in the dashboard to the code module in the engine compartment by three "Receive", "Transmit" and "Ground" lines.
Power for the keyboard, the code sender and the code module is applied only when an ignition key of a three-position ignition switch is moved from the "off" to the "on" position. When the ignition key is moved further to the "start position" power is applied to a starter relay which will allow starter current to flow to a starter motor if the semiconductor switch has been closed by the code module.
In order for the semiconductor switch to be closed, it is necessary for an "AND-OR latch" to have been operated. The latch is operated in response to the momentary presence of a "good word" signal. Because of the latch characteristic, the output from the latch, after momentary enablement, returns through its internal OR gate to an input of its internal AND gate. The latch therefore remains enabled by DC power on the remaining terminal of the internal AND gate. Accordingly, the latch will provide an output as long as DC power is supplied.
Hauer emphasizes that a "good word" signal will transfer the AND/OR gate latch into the high state and will open up the starter transistor to prepare for the immediately following start command. The transistor will allow the start command to be executed and will remain conductive until the engine is turned off.
With respect to the keypad and the code sender in the dashboard, the processor within the code sender is programmed so that after the ignition key is turned "on", there is a search in the data memory for a "status byte". If the status byte indicates that the unit is disarmed, the processor reads the operating code word in the data memory. The code word is then delivered to the line interface and the vehicle can be started.
If the status byte indicates that the unit is armed, the processor delivers a code request to the key board interface. After the code word is entered at the keyboard, the processor scans the keyboard and passes the entered code word to the line interface.
It is to be noted that although Hauer includes a "program timer" in his code module, the only purpose of the timer is to respond to a "bad word signal", so that the occurrence of more than three bad word indications will disable the security circuit. It is to be further noted that there is no timer in the code sender.
Another example of complexity is demonstrated by Nieuwkoop, U.S. Pat. No. 4,864,292, in which a complex identification system includes an induction coil acting with respect to an integrated circuit responder for use in entering a normally locked door by detecting variations of an electromagnetic field.
Even more complexity is associated with Fukamachi et al, U.S. Pat. No. 4,862,139, which discloses a key operated antitheft system with two embodiments. In the first embodiment, a door key is inserted into a key slot containing a sensing device. This generates a signal in a control circuit mounted in the vicinity of the dashboard.
In the second embodiment, a key having circuitry is inserted into a key slot. This energizes the door lock device and the protection device which includes a third key sensing portion and an engine start disabling circuit. The signal generated by the control circuit merely provides a ground to the pre-existing solenoids associated with the fuel injection device and the motor.
In Fukamachi a starter cut relay is kept energized until the alarm permission mode is canceled to prevent an engine from starting. The switching action requires that a switch must be closed to permit starting. In addition since the relay operates from a dashboard located control circuit, it logically is in the vicinity of the control circuit.
The Fukamachi vehicle is provided with a protection device, which is a third key sensing portion of a similar construction to that of a second key sensing portion, an engine start disabling circuit, and an anti-theft alarm circuit. The key sensing portion is in the key inserting hole of an ignition switch. The engine start disabling circuit and the anti-theft alarm circuit are rendered operative in response to output signals from a keyless lock detecting circuit, and are rendered inoperative by a signal output circuit. Thus the protective circuitry has a sensing portion associated with an entry key, and is at a readily accessible location. A signal is extended to conventional relays to supply them with a ground or a voltage, so that the system is easily defeated by grounding the lead from the signal source.
In Fukamachi even if one can enter the passenger compartment after breaking the door lock, one cannot overcome the engine start disabling circuit without using the proper key. The start disabling circuit is formed by conventional relays which are supplied with a ground or signal from a sensing circuit associated with the key. Thus the system is easily overcome by grounding.
Finally, Fukamachi states "The open-closed state detecting circuit is adapted to supply the engine start disabling circuit and the alarm circuit with a signal indicative of the open states or closed states of the various coverings (doors, trunk, bonnet, etc.)". This is a further reference to the so-called "disabling circuit" which is readily accessible.
Complexity also characterizes Adkins et al, U.S. Pat. No. 4,463,340, where an ignition control switch is within a receiving module and remote from the ignition. Moreover, the sending module includes a comparator which detects an input code and actuates an encoder if there is a match with a code in storage. As a result, the system can be defeated by opening the module and activating the encoder. Adkins also provides transmission of encoded signals upon the power supply of an automobile in a way that interferes with proper functioning of circuitry that responds to the code signals.
Another easily defeated system is to be found in Adkins U.S. Pat. No. 4,438,426 which shows a decoder for transmitting a signal to an ignition enabling circuit. The decoder produces an enable signal after decoding a preselected code. An ignition enabling mechanism is connected with a decoder for selectively enabling an automotive ignition to be operated in response to the receipt of the decoder enable signal. An automatic reset is connected with the ignition enablement for automatically disabling the ignition within a predetermined duration of ceasing operation of the ignition. An electrical jack which is operatively connected with a decoder is mounted to receive an electrical plug from the exterior of the vehicle.
As in Fukamachi, the switch in Adkins '426 that is controlled by a decoder and is in the vicinity of an ignition switch where it is readily accessible to an unauthorized user. Confirmation of the driver's compartment location of the decoder is seen by the use of a valet switch which must be near the driver. The objective in Adkins is to have an alarm system that will keep unauthorized drivers out of the driving compartment, not to prevent starting of the engine. In any event, the Adkins' system is easily defeated by pulling out the valet switch and applying battery power to the wiring of the switch. Adkins emphasizes that not only will the car start without the ignition key being used, but the alarm system will be shut down as well.
Accordingly, it is an object of the invention to facilitate the protection of devices. A related object is to facilitate the protection of movable devices. Another related object is to facilitate the protection of vehicles, including automobiles and utility vehicles.
Another object of the invention is to maintain the protection of vehicles even when the integrity of a key-lock arrangement is compromised. A related object is to keep the vehicle inoperative after a conventional inhibit start arrangement is disabled.
A further object of the invention is to achieve protection without the need for a warning system. A related object is achieve protection without the need for tracing signals.